Poland’s Adrian Meronk shot a closing 66 to beat home favourite Adam Scott to the men’s Australian Open title by five shots while South African Ashleigh Buhai won the women’s event.
England’s Kipp Popert won the All Abilities title for para-golfers.
Meronk became the first Pole to win on the European Tour at July’s Irish Open and added a second title in Melbourne.
The 29-year-old left former Masters champion Scott trailing at Victoria with his superb four-under final round.
South Korea’s Jiyai Shin missed a five-foot birdie putt that would have forced a play-off in the women’s event, played alongside the men’s for the first time at the Australian Open.
Meronk, a contender for Europe’s Ryder Cup team next year, enjoyed a much more dominant victory and sealed his triumph with a 40ft eagle putt on the 18th.
He said: “To finish like that on the 18th hole, it’s unreal.
“Adam was always my role model growing up. Beating him in the final group in front of the big crowds in Australia is just quite an unbelievable experience.”
Former world number one Scott had a one-shot overnight lead but he unravelled late in the final round to shoot a 72 and miss out on reclaiming a trophy he first won in 2009.
Grace Kim gave home fans hope as she worked her way into a share of the lead with Women’s British Open champion Buhai, but a double-bogey on the 18th left the 21-year-old in fourth as compatriot Hannah Green took third.
The men’s and women’s Australian Open events had equal prize money of £940,000.